Sticking with an old engine can also lose you a lot of time. Particularly, I suspect, when it's this one. Same piece of shit with the same limitations and issues as every Bethesda game, saddled with massive technical debt from the first instant. This thing was made with sword-and-horse CRPGs in mind - not at a huge scale, either - and works sorta OK-ish for Fallout... and now they wanted to tack on space flight, too.

The metro in one of the Fallout 3 expansions was famously basically... a hat, on an NPC. That's the sort of stuff you can end up doing if trying to do new/unsupported shit in old engines - and this is not getting any younger. Working out bugs, missing features, odd edge cases, old hacks that "just fixed something real quick" 15 years ago, trying to dig up old documentation...

Time adds up fast, those sunk costs are gonna fuck you up. And then you end up releasing Starfield.

Still don't know exactly how that translates into "we could only make one interior and copy-pasted it a hundred times" though.